Power-operated dolly

ABSTRACT

An apparatus for electrically, as well as manually, moving heavy objects up stairways. A group of wheels at each side of a dolly frame are arranged about a common axis, each group being operable about the axis of an electric drive and each wheel of each group being rotatable about its own axis, but capable of being locked against forward rotation when required. A tilting mechanism facilitates loading of a piece of equipment on the apparatus.

United States Patent Gross [$4] POWER-OPERATED DOLLY Oct. 17, 1972- 3,515,401 6/1970 Gross ..280/5.26

[72] Inventor: Eshcol Silas Gross, 3320 1/2 Delmar south San Gabriel, m Primary Exammer-ILeo Fnagha l h 221 Filed: June 1, 1971 J Cam [2]] Appl. No.: 148,639 [57] ABSTRACT An apparatus for electrically, as well as manually, [52] US. Cl. A, 28015.26 moving heavy objects up stairways. A group of wheels [51] Int. Cl. ..B62d 5/02 t each side of a dolly frame are arranged about a [58] Field of Search.......................280I5.26; 180/8 A common i ach group being operable about the axis of an electric drive and each wheel of each group [56] Rderenm Cited being rotatable about its own axis, but capable of UNITED STATES PATENTS beingiocked against fortv ard rotation when required. A tilting mechanism facilitates loading of a piece of 2,7 Loam 6t 8] on 3,346,269 10/1967 Soto ..280/5.26 3,450,219 6/ l969 Fleming ..180l8 A 9 Claims, 9 Drawing Figures I00 72 7 8a 2a v H o E 8.9 o :75 72 3a 44 I" 34 Q 74 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to moving equipment, and relates more particularly to electrical poweroperated dollies, or hand trucks, for moving heavy articles or appliances, such as refrigerators, furniture and the like, up stairways.

2. Description of the Prior Art There are various types of manual and poweroperated dollies and trucks. When trying to move heavy objects and articles, especially up stairways, several difficulties are encountered.

One difficulty is that, with prior art devices, it is generally necessary to require more than one man to operate a large, heavy load. When the load is to be brought up a stairway, it becomes an even greater problem because of the lack of working room for enough men to get around such devices while on the stairs.

Another difficulty is that the wheels of the dollies are located near the lifting edge of a load, causing the weight to be primarily positioned to the front, or free edge, of a step tread, thereby very easily causing an unbalanced condition to occur with possible loss of the load and injury to the operator. In addition, where there is poor construction of the steps the poorly distributed weight is, therefore, apt to break off the front, or free edge, of the step tread.

SUMMARY OF THE INVENTION The invention comprises a frame with oppositelydisposed side frame members secured together by cross members. At the lower end of the frame and to the rear thereof, there is a transversely-extending axle assembly which is fixedly connected intermediate its ends to a drive mechanism for rotating the axle. The axle is operably supported adjacent each of its outer ends by bearing sleeves, each of which is fixedly secured to the free ends of arm members. These arm members are pivotally connected to the lowermost point of the oppositely-disposed side frames. In addition, there are provided sleeve members positioned between each bearing sleeve member and each side of the drive mechanism. The sleeve members are freely supported on the axle for rotation thereon. A centrally-positioned support plate for mounting a motor in the drive mechanism is fixedly secured to each sleeve member for rotation therewith.

The free ends of the axle are adapted to receive a group of wheels in such a manner as to be rotated with the axle by the motor and drive mechanism. However, each wheel of each group is free to rotate about its own axis and each wheel is provided with one directional locking means to prevent the wheel from rotating in a forward direction.

There is also provided an adjusting and locking lever for positioning the motor and drive mechanism in various required positions during the operation of the dolly.

When the dolly is needed to transport a load over a long distance, such as a floor of a large warehouse, an auxiliary wheel support is arranged to be removably attached to the upper, free end of the dolly frame, and after a load is secured to the dolly the frame is brought back to rest on the auxiliary wheel support and the wheel groups, thereby permitting the dolly frame and load to take a horizontal position during transportation of the load from one area to another, without the need of an operator to support the load.

OBJECTS AND ADVANTAGES OF THE INVENTION It is an object of the invention to provide an apparatus, for moving heavy appliances and other pieces of equipment up stairways, having a power-operated drive means.

Another object of the invention is to provide an apparatus of this character which may be readily operated by one person.

Still another object of the invention is to provide an apparatus of this character whereby heavy equipment and the like may be easily balanced for safe movement up stairways.

A still further object of the invention is to provide an apparatus of this character that is capable of movement under its own power.

A further object of the invention is to provide an apparatus of this character having means positioning an article, such as a heavy appliance, in a close, tight area.

Another object of the invention is to provide an apparatus of this character that is simple in construction, relatively easy to operate, and that is rugged and reliable under various operating conditions.

Other characteristics, advantages and objects of my invention can be more readily appreciated from the following description and appended claims. When taken in conjunction with the accompanying drawings, this description forms a part of the specification wherein like references and characters designate corresponding parts in several views.

DESCRIPTION OF THE DRAWINGS Referring more particularly to the accompanying drawings, which are for illustrative purposes only:

FIG. 1 is a side-elevational view of apparatus embodying the invention in an upright position;

FIG. 2 is a rear-elevational view thereof;

FIG. 3 is an enlarged sectional view taken on line 3- 3 of FIG. 2;

FIG. 4 is a side-elevational view of apparatus embodying the invention in an operating position;

FIG. 5 is an enlarged sectional view showing the motor and motor support in an alternative position;

FIG. 6 is a sectional view taken on line 6-6 of FIG.

FIG. 7 is a schematic view of the operating switch;

FIG. 8 is a fragmentary view of the upper end of the apparatus, including an additional wheel assembly; and

FIG. 9 is a view taken in the direction of arrows 9-9 in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, the apparatus comprises a frame, indicated generally at 10, having oppositely-disposed side frames 12 and 14, respectively. Each of said side frames is in the shape of an elongated, narrow, inverted "U" which is narrower at the top than at the bottom. In order to reinforce the arms of the U"-frame parts 12 and 14 in longitudinal spaced relation, there are provided a plurality of interconnecting reinforcing cross members l6, l8 and 20, said cross members being secured to the respective arms of the U"-frame part by means of welding, brazing or the like.

There are, also, transverse reinforcing members 22, 24 and 26 interconnecting said "U-frame sides 12 and 14, said transverse reinforcing members having their ends welded, or otherwise suitably secured to the corresponding arms of the U"-frame sides.

The rear arms of each U"-frame side have a portion 30 which is inclined forwardly and downwardly, the forward end of said portion 30 being secured to the lower end of each corresponding forward arm, as indicated at 32, by means of welding, brazing or other suitable means.

Indicated generally at 34 is a support means for supporting items being handled which is attached to the lower end of the front arms of the U"-frame side, said support means comprising an angle-iron member having a forwardly-projecting blade 36, the other part of the angle iron, indicated at 38, being secured to the forward side of the forward arms of the U-frame sides by welding, brazing or other suitable means.

Pivot-support plates 40 are secured to the lowermost ends of the U"-frame sides by welding, or other suitable means, and are located at the outer sides of said U frames. Suitable pivots 44 are secured to the respective plates 40, as seen in FIG. 2. Rotatably mounted to the pivots 44 are linking arms 46 having holes in which said pivots 44 are received, so that said forward ends of linking arms 46 are pivotally mounted thereon. The opposite ends of said linking arms 46, which extend rearwardly of the side frames 12 and 14 are secured to bearing sleeves 48 by means of welding or the like, said bearing sleeves being operably supported by an axle assembly 50 which is free to rotate within the bearing sleeves 48.

Positioned intermediate the ends of the axle assembly 50 is a drive means 52 which is operably attached to the axle and is operated by motor 54. Said motor 54 is centrally positioned within the frame and is adjustably supported by a mounting plate 56 adapted to receive both the motor and drive means 52. Suitable sleeves S8 and 60 are rotatably disposed over the axle 50 and are arranged on opposite sides of said drive means, whereby said mounting plate 56 is secured thereto by welding, or the like, for rotational adjustment about the axle assembly 50. A mounting plate is provided with lower, outwardly-extending arms 62 and 64 for securing to the plate 56, as mentioned above, and a slot 66, whereby the drive means can properly receive the transverse axle 50, as seen in FIGS. 2, 3 and 5.

The outer ends of the axle assembly 50 are removably attached to wheel-support frames, indicated generally at 68. The wheel-support frames, or assembly, comprise a pair of oppositely-disposed plates 69, each of which has a central opening therein to receive the ends of the axle assembly 50 in such a manner that the wheel-support frames rotate with the assembly about a common axis. Said side plates 69 of.

each wheel-support assembly 68 are spaced apart and are formed with correspondingly-arranged arms 70 between which are operably-mounted wheels, indicated generally at 72, which have rubber tires 73 thereon. There are four arms for each side plate of each wheel frame and four wheels for each frame, said wheels being annularly spaced apart. Each of the four wheels is free to rotate about its own axis which is provided by pin 74. However, under certain conditions the wheels are required to rotate in one direction but are prevented from counter-rotation. There is provided adjacent each wheel 72 a means for limiting rotation of the wheel in one direction. This means comprises a ratchet wheel 76 fixedly connected to wheel 72 for rotation therewith, and is positioned between the outer plate 69 and the inner face of said wheel 72. Located adjacent the teeth of the ratchet wheel 76 is a pawl 78 being pivotally mounted to the plate 69 at such a point that the contacting end of the pawl is furthermost from the center point of the pivot pin 79 while the free, closest end is operably connected to a spring-loaded rod 80, as seen in FIG. 6. A biasing means, such as spring 82, is positioned on the rod 80 and held in tension by the rod-support member 84 and shoulder 86 of the rod 80. When the pawl is positioned, as shown in dotted lines, the wheel 72 is free to rotate in any direction, that is forward or backward. However, when the pawl is placed in a position where the free end of the pawl is in direct contact with the ratchet wheel, the wheel can only rotate in one direction. The means for limiting rotation of the wheel is arranged in relation to the wheel 72 so as to prevent the frame from moving in a forward direction, particularly when carrying a load up a staircase. To prevent a mishap from occuring, each limiting means adjacent each wheel is provided with a lever 88 for adjusting the pawl into or out of engagement with the ratchet wheel 76, along with marking 89, shown as paint strip, to indicate when the pawl is locked into place. That is, the lever 88 is always positioned in the identical manner as the pawl and it may be readily seen by the operator when the lever 88 does or does not correspond to the direction he requires by checking the direction of the lever 88 with that of the marking 89. (See FIGS. 1 and 3) When the apparatus is to be used to haul a load, the support means 34 is slipped under the load, in the position shown in FIG. 1, at which time the wheels 72 are approximately four inches above ground level and should be unlocked to rotate in both directions. The frame 10 is then pulled rearwardly at its upper end and will pivot on the lower end of the forward arm of the side frames, the fulcrum point being at 90. The frame and load will assume the general angle as shown in FIG. 4, wherein the frame 10, along with the load, is evenly balanced over a pivot point provided by the axle 50.

However, when a load is required to be transported from one level to another, that is up or down a stairway, the pawls 78 are locked into engagement with the teeth of the ratchet wheels, as seen in FIG. 6. This is accomplished by rotating each lever 88 so that said lever is aligned with and in the same direction as its corresponding marking 89. Since the wheels 72 are locked from forward rotation, the motor 54 is energized by any suitable power supply, causing movement to the drive means which, in turn, rotates the axle 50. Hence, the wheel-support frames will rotate with the axle, since said axle is fixedly connected thereto. The suitable power supply referred to can be provided by plug 92 of the electrical line 94 into a typical electrical outlet, not shown, or by connection to a battery which can be carried by the dolly frame 10, said battery, also, not shown. A switch means, indicated generally at 96 in FIG. 1, is provided in the electrical line 94 for controlling the on and off operation of the motor, as well as backward and forward movement of the dolly. A more detailed description of the switch means will hereinafter be described.

As an example, if the load 96, seen in FIG. 4, is to be transported up a staircase, all the wheels are locked from forward rotation. A motor 54 is energized to rotate the wheel assemblies 68 in a clockwise direction, at which time the assemblies pivot about the wheel 72 which is engaging the surface 98. This, then, allows the succeeding wheel 72 to engage the first tread of the stairs and, thereafter, each succeeding wheel will engage each succeeding tread, thereby permitting the operator of said dolly to control and operate the frame singularly with ease.

It can be readily understood that the reverse of the above operation will provide the necessary operation of transporting the load down a staircase.

It, also, is to be understood, of course, that when the appliance, or other load, is moved onto the plate 36 it is secured to the frame by means of the usual mechanism which includes an automatic retractable belt with an automatic ratchet assembly for tightening the belt around the object on the dolly. This mechanism is well known and is incorporated into the dolly but since it is not part of the present invention, except as the means for securing the object on the dolly, it is not shown.

During the above-described operation, the motorsupport plate and the motor are tilted forward and locked into the position shown in FIGS. 1 and 3, whereby the wheels 72 of the wheel assemblies 68 are spaced approximately four inches from the surface 98. The locking means comprises a pair of locking-arm members 100 and 101, respectively. Each arm is pivotally attached to a transverse cross bar 102, which is secured to the leading member of the side frames 12 and 14, and is arranged thereon to receive said motorsupport plate therebetween. As more clearly seen in FIG. 3, said plate 56 is provided at its upper end with oppositely-disposed means for limiting movement of the plate and motor, said means being in an extended lug 103 secured by welding or the like to said plate 56, said outer free end of said lug having a shoe-stop member 104 which engages the cross bar 102. The motor is then locked into the tilt position by locking arms 100 and 101 which are provided with notches 105 for receiving the lock bar 106, the lock bar being fixedly secured to said plate 56 and its free ends extending outwardly from the outer edges of the plate 56, whereby engagement with said locking arms is easily accomplished. (See FIG. 2) Said locking arms 100 and 101 are also provided with an enlarged notch 108 at their outer free ends for locking engagement with a transverse reinforcing member 26, to prevent further movement of the arms.

Referring now to FIG. 5, there is shown the second position of the motor-support plate 56 and motor 54in a nearly vertical arrangement. The plate and motor have been rotated rearwardly and locked into this position by notch 108 which is large enough to simultaneously receive both the locking bar 106 and the transverse reinforcing member 26. The above arrangement is generally used when the dolly is in an upright position just prior to the unloading of an item supported thereon, particularly when the item is to be placed in a restricted area.

For example, if the item is a large appliance which is to be placed between two large structures, such as other appliances or walls, by activating the motor 54 in a counter-clockwise movement the wheel assembly 68 will rotate about the axis of the axle 50 in a forward direction, moving the dolly and load forward into their proper place with ease and little effort on the part of the operator.

Hence, the forward and reverse operation of the motor 54 depends on the proper use of the switch means 96. Said switch means, shown in more detail in FIG. 7, comprises an elongated contact bar 110, of suitable metal, pivotally mounted intermediate its free ends by a mounting pin 112. The contact bar is spaced parallely apart from an insulated bar 114 made from suitable insulated, material, such as hard rubber or plastic, said insulated bar being provided with openings 116 to receive guide pins 118, which are oppositely disposed within said contact bar and adapted to receive a biasing spring 120 for forcing the contact bar 110 upwardly and away from contact with contact pins 122 and 123. These contact pins are removably secured to the outer, free ends of said insulating bar 114. Electrical potential is received through wires 124 and 125, wherein wire 124 directly connects to mounting pin 112 while wire 125 leads to the reversible motor 54. Wires 126 and 127 are respectively connected to pins 122 and 123, the opposite ends of which are attached to the proper contacts in the motor. The forward and reverse components of the motor are well understood and are not shown since they are not part of the present invention, except as a means for operating the direction of said motor. The switch 96 is covered by protective insulation material within the line 94, as seen in FIG. 1.

On occasions, when it is necessary to transport an appliance, or other item, along a flat surface over a long distance, an additional wheel assembly, indicated generally at 130, can be attached to the upper end of the frame 10. Any suitable type of wheel construction can be adapted to fit thereon. However, a four-wheel assembly has been shown for illustrative purposes.

Oppositely disposed and secured to the inner upper ends of the side frames 12 and 14 are sleeve members 132 and 134 which are adapted to removably receive handles 136 of the wheel-support frame 140. Here, too, any suitable means can be used for removably attaching said wheel-support frame. Therefore, pins 142 are shown passing through sleeves 132 and I34, and handles 136.

The wheel assembly is attached to said dolly when said dolly is in an upright position and is, thereafter, lowered to a horizontal position, somewhat parallel to the ground surface 98, this being shown partially in FIGS. 8 and 9.

An extension means is also provided when a load is of such a size and weight that extra leverage is required by the operator to pivot the load about point 90. This means is illustrated as a vertical bar 145 slidably disposed within the frame 10 having support rings 146 affixed to the inner side of the front, transverse reinforcing members 22 and 24, respectively, as shown in FIG. 2. When needed, the bar 145 is extended upwardly from said frame 10, thereby giving added leverage advantage to the operator.

While I have shown and described particular embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

I claim:

1. A stair-climbing, power-operated dolly comprismg:

A. an elongated frame having oppositely-disposed,

parallel side frames and reinforcing members fixedly secured to said side frames;

B. a blade transversely secured to the lower front part of said frame;

C. a pair of linking arms, each being pivotally connected to respective side frames adjacent the lower front part thereof, said arms extending rearwardly and having openings adjacent their rear ends;

D. a bearing sleeve attached to the outer end of each linking arm, said bearing sleeve being axially aligned with said opening in said arm;

B. an axle assembly, including rotatable sleeves thereon, the outer ends of said axle assembly being operably supported within said bearing sleeves of said linking arms;

F. a wheel assembly removably attached at each end of said axle assembly, each wheel assembly having side plates with a plurality of radially-extending, oppositely-disposed arms spaced laterally apart in pairs;

0, wheels operably supported and positioned between said radially-extending arms of said side plates;

H, a drive means operably attached intermediate the ends of said axle assembly;

I. a power-operated motor operably attached to said drive means; and

J. a support plate centrally positioned within said frame and secured to said rotatable sleeves on said axle assembly, said plate having said motor fixedly secured thereto for adjusting said motor between an upright position and a forwardly-inclined position, and vice versa, about the axis of said axle assembly and whereby the wheel and axle assemblies are correspondingly adjusted between a raised and lowered position relative to the surface of the blade and consequently to the dolly supporting surface.

2. The invention defined by claim 1, including means for limiting rotation of said wheels in one direction, said means being positioned within said wheel assembly for positive engagement with said wheels.

3. The invention defined by claim 2, wherein said means for limi n rotatio of said wheels com rises a ratchet wheel fi x d to eac ir p of said wheels for rotation therewith, and a latching pawl adapted to be biased in either a latched or an unlatched position.

4. The invention defined by claim 3, including a positioning lever movably mounted to the outer side plate of each wheel assembly and secured to said pawl, whereby said pawl can be adjusted; and a position marker strip arranged on the outer face of said side plate in a parallel plane with that of said positioning lever when said lever is in a latched position, whereby said latched or unlatched position is visually indicated.

5. The invention defined by claim 2, including locking means for securing said support plate between said upright position and said forwardly-inclined position. 7

6. The invention defined by claim 5, wherein said locking means has a pair of oppositely-disposed locking arms pivotally supported to one of said reinforcing members located at the front of said frame, said locking arms being provided with notches; and said locking means includes a lock bar fixedly secured to said support plate and adapted thereon to be received within said notches of said locking arms.

7. The invention defined by claim 5, including an extension means having an elongated bar slidably mounted to said frame and being upwardly extendable from the top part of said frame when additional leverage is required for pivoting the loaded frame.

8. The invention defined by claim 5, including a switch means having a central mounting pin, a contact bar movably supported by said mounting pin at one end of said pin, and an insulated bar fixedly secured to the opposite end of said bar, said contact bar and said insulated bar being held in parallel relation to each other by biasing means oppositely disposed at each side of said mounting pin, said insulated bar having a contact pin secured adjacent each end thereof for selective contact between said pins and said contact bar, whereby said motor can be energized for forward or reverse operation.

9. The invention defined by claim 1, including an auxiliary wheel assembly and means for removably attaching said means to the upper part of said frame rearwardly and at right angles thereto. 

1. A stair-climbing, power-operated dolly comprising: A. an elongated frame having oppositely-disposed, parallel side frames and reinforcing members fixedly secured to said side frames; B. a blade transversely secured to the lower front part of said frame; C. a pair of linking arms, each being pivotally connected to respective side frames adjacent the lower front part thereof, said arms extending rearwardly and having openings adjacent their rear ends; D. a bearing sleeve attached to the outer end of each linking arm, said bearing sleeve being axially aligned with said opening in said arm; E. an axle assembly, including rotatable sleeves thereon, the outer ends of said axle assembly being operably supported within said bearing sleeves of said linking arms; F. a wheel assembly removably attached at each end of said axle assembly, each wheel assembly having side plates with a plurality of radially-extending, oppositely-disposed arms spaced laterally apart in pairs; G. wheels operably supported and positioned between said radially-extending arms of said side plates; H. a drive means operably attached intermediate the ends of said axle assembly; I. a power-operated motor operably attached to said drive means; and J. a support plate centrally positioned within said frame and secured to said rotatable sleeves on said axle assembly, said plate having said motor fixedly secured thereto for adjusting said motor between an upright position and a forwardly-inclined position, and vice versa, about the axis of said axle assembly and whereby the wheel and axle assemblies are correspondingly adjusted between a raised and lowered position relative to the surface of the blade and consequently to the dolly supporting surface.
 2. The invention defined by claim 1, including means for limiting rotation of said wheels in one direction, said means being positioned within said wheel assembly for positive engagement with said wheels.
 3. The invention defined by claim 2, wherein said means for limiting rotation of said wheels comprises a ratchet wheel fixed to each of said wheels for rotation therewith, and a latching pawl adapted to be biased in either a latched or an unlatched position.
 4. The invention defined by claim 3, including a positioning lever movably mounted to the outer side plate of each wheel assembly and secured to said pawl, whereby said pawl can be adjusted; and a position marker strip arranged on the outer face of said side plate in a parallel plane with that of said positioning lever when said lever is in a latched position, whereby said latched or unlatched position is visually indicated.
 5. The invention defined by claim 2, including locking means for securing said support plate between said upright position and said forwardly-Inclined position.
 6. The invention defined by claim 5, wherein said locking means has a pair of oppositely-disposed locking arms pivotally supported to one of said reinforcing members located at the front of said frame, said locking arms being provided with notches; and said locking means includes a lock bar fixedly secured to said support plate and adapted thereon to be received within said notches of said locking arms.
 7. The invention defined by claim 5, including an extension means having an elongated bar slidably mounted to said frame and being upwardly extendable from the top part of said frame when additional leverage is required for pivoting the loaded frame.
 8. The invention defined by claim 5, including a switch means having a central mounting pin, a contact bar movably supported by said mounting pin at one end of said pin, and an insulated bar fixedly secured to the opposite end of said bar, said contact bar and said insulated bar being held in parallel relation to each other by biasing means oppositely disposed at each side of said mounting pin, said insulated bar having a contact pin secured adjacent each end thereof for selective contact between said pins and said contact bar, whereby said motor can be energized for forward or reverse operation.
 9. The invention defined by claim 1, including an auxiliary wheel assembly and means for removably attaching said means to the upper part of said frame rearwardly and at right angles thereto. 